Figure 8a. Enterovesical fistula. (a) Contiguous transverse CT scans obtained with intravenous and oral contrast agents in a 69-year-old woman with longstanding Crohn disease show a heterogeneous soft-tissue mass (M) associated with thickened ileal loops and adjacent bladder wall thickening (arrowhead). A small gas bubble (arrow) is present in the bladder lumen. (b) Fluoroscopic image shows contrast agent injection through a communicating enterocutaneous fistula and demonstrates the fistula (arrowhead) between the ileal segment and bladder. Small-bowel adenocarcinoma complicating Crohn disease was proved at surgery.